Copy process and materials for use in same



COPY PROCESS'AND MATERIALS FOR USE IN SAME Robert T. Florence, ParkRidge, 111-, assignor to A. B.

Dick Company, Niles, lll., a corporation of Illinois No Drawing.Application May 11, 1955 Serial No. 501,739

15 'Claims. (Cl. 101-4494 This invention relates to a multiple-copyprocess and to materials for use in the practice thereof. Moreparticularly, it relates to an improvement in the invention describedand claimed in my copending application Serial No. 287,616, filed May13, 1952, now Patent No. 2,748,024.

It is an object of this invention to provide a new and improvedmultiple-copy process for use'in the field of ofiice copy work, and toprovide elements for use in same.

More particularly, it is an object of this invention to provide animprovement in a copy process of the type described in mycopending'application Serial No. 287,616 wherein a master imaged with acomposition containing a water-and-alcohol soluble component of an azodye isbrought into surface contact with copy sheets which havepreviouslybeen wetted with a solvent for the dye-forming component forleaching some of the dye-forming component for transfer from theimagedportion of the master tocorrespondingareas of the copy sheet and inwhich the copy sheet is provided with a component whichcauses reactionof the dye-forming component'upon transfer to form the dyestufis, and itis arelated objectto produce new and'improved materials-for use in same.

In theprcferred concept of the invention described and claimed intheaforementioned copendingapplication, a

diazo compound and-a coupler for reactiontherewith' are both containedin' a non-coupling-state in the transfer coating of a carbon sheet ormother-compositions for usein. the preparationv of animaged master; Inthe concept describednthe. diazo compound is 'stabilizedagainst'reactionwith the coupler by'conversion'to a' diazonium' saltand/or. by adjustment .to maintain acidic conditions,"

as,b.eloW-a"pH"of 3.5 to prevent coupling. The fluid which is used towet thesurfaces of the copy sheetsprior to contact with theimagedmasteris' :formed of a solvent for the stabilized diazo compoundand coupler and contains a basic medium which, upon leaching of thediazo and couplerfrom the imaged master for transfer to' the copy esses.

2,873,671 Patented el). 7 i7, i959 In the system of the aforementionedcopending application, the only time that a dyestuif isformed is in thecopy sheets after they have been passed through the duplicating machine,and the dyestuifwhich is formed at this stage can be an insolubledyestuff as distinguished from the highlywater-and-alcohol soluble dyeof which the copy is formed in conventional spirit duplicating 1systems.

Elimination of the dirtiness characteristic of conventional spiritduplicating or hectograph systems is achieved without sacrifice in thesimplicity of the copy process, without sacrifice in the ease of"preparation of the imaged master or in the correction or modificationof-the imaged master, and in the use of the imaged master to producecopies, or in the number of copies of good quality that can beproduced.

It has now been found, by way ofa still further improvement, that thecharacter ofthe copy and the stability of the transfer sheet and themaster imaged therefrom can be greatly improved when, instead of makinguse of a coupler and a stabilized diazo compound as separate componentsin the imaging compositiomuse is made of a complexcompound in the fromof a diazo salt of a coupler formed by a non-couplingreaction of thediazo compound with the coupler in acidic medium.

Thesalt that is formed is sufiiciently soluble in the 'spirit fluidsformed of alcohol and/ or a mixture of alcopresent in the image onthe'surface of the master can be leached for transfer from the imagedareas of the master to corresponding areas of the copy sheets. If thefluid applied to the surface of the copy sheets contains a base, such asdiethanolamine, monoethanolamine, or other organic base amines, sodiumhydroxide, ammonium hydroxide or the like inorganic bases, or if thecopy sheets contain a base or alkali incorporated therein, as duringmanufacture or by application subsequent to manufacture, or if the copysheets onto which the salt has been leached from the master for transferto the copy sheets are subsequently wet with a second. fluid containing.a base or alkali in solution, the adjustment of pH toward the alkalineside is sufiicient to initiate coupling reaction between the componentsof the saltto form the corresponding azo dyestufi or monoazo dye.

A number of very important and-distinct advantages and improvements areachieved by the use of the couplerstabilized salt instead of thecouplerand stabilized diazo compound as separate components, as in the processdescribed in the copending application. From the standpoint of shelflife, and conditions of use in storage, the

coupler-stabilized diazo salt employed in the practice of this inventionenjoys considerably'greater stability as compared to the system whereinuse is made of a stabilized diazo compound as a component separate andapart from the coupler. As a result, the coupler-stabilized diazo saltor the diazo salt of the coupleris capable of storage over extendedperiods oftime and under differing atmospheric conditions withoutdestruction or decomposition, and its resistance to decomposition andlight is also greatly improved thereby markedly to enhance the servicecondi tions and life or the ,imagingcomposition, the transfer sheetsformed thereof, and theimaged master.

More important from. the standpoint. of the .copy process itself, it hasbeen found that the presence of the diazo and coupler in a singlecompound in the ratio in which they react to form the dyestutf insuresintimate contact and immediate availability of the components necessaryfor reaction to form the dyestuff in the copy sheets. As a result,reaction takes place more quickly and more completely, and full use ismade of all the diazo and coupler in dye formation to produce copy.

Still more important from the standpoint of the character of the copyand the intensity of the copy produced, as well as the number of copiesavailable, is the fact that the presence of the diazo and coupler in asingle compound militates against the extraction of one component ingreater amounts than the other. In the system wherein the diazo ispresent in an imagining composition as a compound separate and apartfrom the coupler, the more soluble component, such as the coupler, isusually extracted in greater amounts than the other with the result thatless copy is produced, and the copy is of inferior quality. By way ofillustration, it may be assumed in a process of the type described inthe aforementioned copending application that the coupler is moresoluble in the fluid than the diazo compound. If the coupler and diazoare present in substantially equal proportions in the imaging material,then the fluid on the surface of the copy sheets brought into contactwith the imaged master will tend to leach larger amounts of coupler thandiazo from the image. While this may result in the production of copy ofhigh intensity at the start, soon the image, or at least the surfaceportion thereof, will become exhausted or depleted of coupler, with theresult that the intensity of copy produced will diminish greatly beforeall or even a good part of the diazo compound has been employed. As aresult, any fraction of the diazo compound will be used, and an equallylarge fraction of the coupler will be wasted. The number of copies ofgood quality produced Will be less than the amount that should have beenproduced in proportion to the fraction of diazo which remains unused orinadequately used in the imaged master.

If, on the other hand, the ratio of coupler to diazo is increased in theimaging material to compensate for the greater solubility andpreferential extraction of the coupler, the concentration of theessential dye-forming components in the imaged master will of necessityhe reduced. This will result not only in reduction in the number ofcopies that can be made available, but the intensity of the copiesproduced throughout the run will be similarly diminished.

When, however, in accordance with the practice of this invention, thediazo and coupler are present as a single stabilized soluble compound,one equivalent weight of diazo will be removed with one equivalentweight of coupler. As a result, a maximum amount of the dye-formingcomponents may be embodied in the imaging material. Only the amount ofcoupler necessary for reaction with the diazo will be leached with thediazo from the imaged master for use in production of the dyestuff.

Relatively little, if any, unused diazo Wiilremain in the imagingmaterial Without an equivalent amount of coupler present for reactiontherewith to form the monoazo dye. As long as the rate of solution iscontrolled and remains substantially uniform, the intensity of copy willhave very little variation from beginning of the run to the end. Fullutilization can be made of the dye-forming components formulated inhigher concentrations in the imaging material thereby greatly toincrease the number of copies of good quality that "can be produced. Aspreviously pointed out, the coupler and diazo are so intimatelyassociated together in the compound that the coupling reaction takesplace substantially completely and immediately upon adjustment of the pHto form the dyestuff in the copy sheets. These and other advantages areavailable in the practice of this invention.

The coupler-stabilized diazo compound can be prepared by combining analkaline solution of the sulfonic acid coupler compound with an acidsolution of the diazo in which sufiicient free acid is available to morethan neutralize the free alkali in the solution of the coupler to form amixture having a weakly acid pH, such as in the range of 6.0-6.5. By wayof example, l-naphthol-S amino-3,6 disulfonic acid (mono sodium salt) inalkaline solution can be added slowly to p-diazo dimethyl aniline toform the p-diazo dimethyl aniline salt of l-naphthol-S amino-3,6disulfonic acid. 2,3 dihydroxy naphthalene-6 sulfonic acid in alkalinesolution can be combined with p-diazo diethyl aniline to form thep-diazo diethyl aniline salt of the 2,3 dihydroxy naphthalene-6 sulfonicacid.

The 2,3 dihydroxy naphthalene-6 sulfonic in alkaline solution can becombined with an acid solution of p-diazo-N ethyl-N hydroxy ethylaniline to form the p-diazo-N ethyl-N hydroxy ethyl aniline salt of 2,3dihydroxy naphthalene-6 sulfonic acid. l-naphthol-8 amino- 3,6disulfonic acid sodium salt in alkaline solution can be combined withp-diazo diethyl aniline in acid solution to form the correspondingp-diazo diethyl aniline salt of 1-naphthol-8 amino-3,6 disulfonic acid.l-naphthol-6 amino-3 sulfonic acid in alkaline solution may be combinedwith o-anisidine diazo in acid solution to form the correspondingo-anisidine diazo salt of l-naphthol-G amino-3 sulfonic acid.l-naphthol-S sulfonic acid in alkaline solution can be combined witho-anisidine diazo in acid solution to form the corresponding o-anisidinediazo salt of l-naphthol-S sulfonic acid.

As an example of the formation of a coupler-diazo salt, one molecularweight of a sulfonic acid coupler is dissolved in water at an alkalinepH. A separate acid pH solution is formed of an equivalent molecularweight of the diazo compound. The alkaline solution is added slowly tothe acid solution with vigorous stirring to maintain a uniform mixture.The free acid content .in the second solution is preferably greater thanthe free alkaline content of the first by about ten percent. The volumeof the two solutions can vary widely without changing the course of thereaction. The pH of the final solution will usually be below 7 andpreferably within the range of 66.5 for best results, and thetemperature should be held at about room temperature or lower. For amore detaled description of the reaction to form a corresponding salt,reference may be had to the U. S. Patent No. 2,525,75l.'

By way of illustration, but not by way of limitation, description willnow be made of the preparation of a transfer sheet which makes use ofthe coupler-stabilizer diazo compound and the use of the transfer sheetin the preparation of an imaged master and in the production of copytherefrom.

Example I A carbon-type transfer sheet is formed by coating :1thin'fibrous sheet of paper or the like with a composition compounded ofthe following materials:

11% by weight carnauba wax 15% by weight oxidized microcrystalline' wax15 by weight heavy mineral oil 13% by Weight light mineral oil 1.5% byweight sodium oleate 44.5% (by weight coupler-stabilized diazo complexcompoun The composition is heated to a temperature of about to C. forapplication as a hot melt onto the surface of the base sheet inconcentrations ranging from 15 to 20 pounds per 3,000 square feet ofsurface area.

When applied as a hotsrnelty.thei compositionapplied? as a coating-tothe surface of-....the base1sheet-remains as a substantially separatedlayeron .thesurfacetoform, a transfer coating capable of .displacement,onto materials in surface contact therewith responsive to theapplication of force.

naphthol-S sulfonic acid;-o-anisidine diazo-l naphthol-6- amino-3sulfonic acid; 6 benzoyl amino-4 methoxy toluene-3 diazo salt of1-naphthol-6"amino-3*sulfonic acid, or the like. coupler-stabilizeddiazo complexcompounds which are soluble in alcohol and water.

Example 11 vFor preparation of the imaged-master, the'coated carbonsheet manufactured inaccordance with Example I, ispositioned with thecoated side at'surfacecontact with ,the prepared surface of a. suitablemaster, and the; coating is displaced from th'e carbon-sheet'to themaster to form the mirror image in responseto forces applied against theuncoated side of the. carbon sheet, as by means of a stylus or otherwriting tool, typewriter key, die impression, or the like.

Instead of forming the image on the master sheet by transfer of portionsof the'coating from the described carbon sheet, the image maybe-formedon the master sheet directly by printing or by the application of-acomposition containing the coupler-stabilized diazo complex in asuitable carrier, such as when contained 1n a writing crayon, in atypewriter ribbon, or in a writing fluid or 111k.

Example III For the production commune copies, the imaged masterprepared in accordance with Example II is mounted ona cylinder of arotary duplicating machine of the conventional type used for spirit orhectograph processes. The fluid appliedto the surface of thecopy sheetsin advance of contact with-the mastermay be formulated to contain thefollowing;

12% by weight diethanolamine, 3% by weight Celloso1ve" by weight water75% by weight-methanol As the :wetted, surfaceslof thecopy sheets arebrought into surface contact with the imaged master' between theimpression rollerand the-cylinder, some of the couplerstabilizeddiazo-complex is -,.'dissolved from the. surface portion of the image.and is transferre'dto'the .corre-i sponding areas of thecopyJsheetwherethe diethanol amine functions to adjust the pHlevel'foreffecting the coupling reaction to form .a .vvater insolublemonoazodyestufi in direct image in the -.copy sheets, 7

From observation, it will become evident that the Instead of applying.the coating materials as a hot melt, the compositionmay be appliedfromsolvent solution or aqueous dispersionbyother dyestufif is formed in thecopysheets as distinguished from theirnaged master, otherwisetransfer of.the coupled reaction product would bemorefdifiicult to achieve undertheconditions described and ,very faint,,if any, copy would result. Colordevelopment takesplace rather quickly once the COUPICIEStQbiliZfid diazocompouudhas been adjustedtoward the'alkaline side by the alkali me- 6dillm: to form, the dyestufi. .Therapysheets--are-.capable of beinghandled: almost immediately; without fear? of? set-'ofi =orsmear,because. thecolor produced is rather permanent and substantiallyinsoluble in character.

The number of copies secured depends: in part: upon, thethickness-of thecoating of which the image is formed and the. amountof-coupler-stabilized. diazo compound contained in the coatingcomposition, as well as the character and quantity-of fluidapplied to:the copysheets for effecting transfer'of thedye components from theimagedmaster forcoupling. to formthe dyestufi. -It--will be apparent, aspreviously described, that-the intensity of the color developed by theazo dye'will remain substantially. uniform throughout .the run :as longas :the amount of coupler-stabilized diazo compound that is. transferredremains substantially; the same. Under-.normalz-con'die. tions, thenumber of. copies produced by the practice of this invention is greaterthan that heretofore: secured by the process described in the'-aforementioned.cop endingapplication. From to 500 copies maybesecured. from ,a single master.

It is desirable-to embody ashigh a concentration ofthe:coupler-stabilizeddiazo compound as, possible-infi the imagingcomposition consistent with-the ability=of the coating to remainasa-film'for. forming the'image. Gen erally, the amount of dye-formingcomponents introduced. as an ingredient in the coating compositiondepends upon the abilityto maintain sufiicient fluidity .under :thewonditions existing in applyingthe coating to achieve -the-desiredcoverage. For the productionof a numberof'copiesof sufilcient intensity,it is desirable to-maintain the con centration of the coupler-stabilizeddiazocompound, in amounts in excess of 40% 'by weight, and preferably inamountsin excess of 60% by weight. When. theconcentration reaches asmuch as.80% by weight; the film-form, ing characteristics of theimagingmaterial are reduced, unless modification ismadea-by the" addition offluidizing,

agents.

When-appliedas a hot melt, or when applied from solvent solution oraqueous emulsion-it isfdesirable :to-secure acoating on the transfersheet having a coating. weight withinthe range of .10 to,30 pounds1per3,000 squarefeet of surface-area. 'When applied in solvent, solutionwith ethyl acetate, tri-chloroethylene,:and the like, alonev or incombination j with "diluents such -asv toluene orbenzene application maybe made of the-coat;- ing composition present in amounts ranging from,20% to 40% solids by weight, or the compositionmaybe formulated'intoan-aqueous dispersion containing 5.40% to 60% by weight solids.

Instead of the fluidemployed in ExampleIILuse may bernade of otherfluids embodying the following compositions.

Example IV Example V 2.0% by weight ammonium :hydroxide 98.0% .by Weightmethanol V The following example provides for'thepr'oduction'of a redcopy from an imaged duplicating master-z ExampZe VL Transfelr sheetcomposition g 7;

44.5 by weight 6'benzoyl amino-4 methoxy t'oluene- 3 diazo salt ofl-naphthol-6 amino 3 *sulfonic acid (couplenstabilized diazo complex)11.0% by Weight carnauba wax 15.0%by weight-oxidized microcrystallinewas 28.0% by weight light mineral oil 1.5% 'by weight. sodium oleateThef'above composition is reduced to a fluid; state by heating to atemperature of about 80-85 C. and then applied by a bolt melt coatingprocess in' weights of about 20-30 pounds per 3,000 square feet ofsurface area onto a suitable base sheet whereby the applied coatingcomposition remains concentrated on the surface of the base sheet foreasy transfer therefrom upon cooling.

A master imaged with a transfer sheet prepared in accordance withExample VI may be used to produce red copy when the fluid applied to thesurface of the copy sheets contains a base such as diethanolamine,monoethanolamine or the like.

It will be understood that the coupler-stabilized diazo complexes may beembodied in other suitable carriers such as combinations of oils inwaxes wherein the oil components are present in higher concentrations toprovide a liquid composition which may be inscribed to form the image ona suitable master sheet. Instead, the coupler-stabilized diazo complexmay be embodied in a waxy system of the type which is applied ontypewriter ribbons for transfer directly to the master to provide theirnage thereon from which copy may be produced.

It will be understood that changes may be made in the method offormulation and application in preparation of the imaging material toform the transfer coating on the carbon sheet or the image on themaster, and that changes may also be made in the techniques foreffecting transfer of some of the imaging material from the master tothe copy sheets for the production of copy without departing from thespirit of the invention, especially as defined in the following claims.

I claim:

1. A transfer medium for use in the preparation of an image duplicatingmaster which is substantially free of color transfer value, comprising abase fabric and a composition present in transfer relation on said basefabric containing a coupler-stabilized diazo compound.

2. A transfer sheet for use in the preparation of an imaged duplicatingmaster which is substantially free of color transfer value, comprising apaper base sheet and a continuous coating concentrated on the surface ofthe base sheet and capable of'substantially complete displacementtherefrom containing a stabilized diazo salt of a coupler which issoluble in a medium selected from the group consisting of water andalcohol and containing a base. v r

3. A transfer sheet for use in the preparation of an imaged duplicatingmaster which is substantially free of color transfer value, comprising apaper base sheet and a continuous coating concentrated on the surface ofthe base sheet and capable of substantially complete displacementtherefrom formed of a wax base and containing a coupler-stabilized diazocompound.

4. A transfer sheet as claimed in claim 2 in which the stabilized diazosalt of the coupler is present in amounts ranging from 40-80 percent byweight in the coating composition.

5. A transfer sheet as claimed in'claim 2 in which the stabilized diazosalt of the coupler comprises a diazo salt of a sulfonic acid coupler.

6. A transfer sheet as claimed in claim 2 in which the stabilized diazosalt of the coupler is a stabilized compound selected from the groupconsisting of p-diazo dimethyl aniline-1 naphthol-8 amino 3,6 disulfonicacid; p-diazo diethyl aniline-2,3 dihydroxy naphthalene-6 sulfonic acid;p-diazo-N ethyl-N hydroxy ethyl aniline-2,3 dihydroxy naphthalene-6sulfonic acid; p-diazo diethyl aniline-l naphthol-B amino-3,6 disulfonicacid; o-anisidine diazo-1 naphthol-S sulfonic acid; o-anisidine diazo-1naphthol-6 amino-3 sulfonic acid, and 6 benzoyl amino-4 methoxytoluene-3 diazo salt of 1 naphthol-6 amino-3 sulfonic acid.

7. A composition for imaging a spirit duplicating master comprising awax-oil base containing a coupler-stabilized diazo compound in the formof a diazo salt of a sulfonic acid coupler stabilized against reactionin acidic medium and which is soluble in a medium selected from thegroup consisting of water and alcohol.

8. A duplicating master comprising a master sheet comprising a waxycarrier and an image on the surface of the master sheet containing acoupler-stabilized diazo complex compound which is soluble in a mediumselected from the group consisting of water and alcohol and containing abase.

9. A duplicating master as claimed in claim 8 in which thecoupler-stabilized diazo complex compound is present in the imagingmaterial in amounts ranging from 40-80 percent by weight.

I 10. A duplicating master as claimed in claim 8 in which thecoupler-stabilized diazo complex compound is a diazo salt of a sulfonicacid coupler stabilized by formation in an acidic medium.

11. A duplicating master as claimed in claim 8 in which thecoupler-stabilized diazo complex compound is a coupler-stabilized diazosalt selected from the group consisting of p-diazo dimethyl aniline-lnaphthol-8 amino-3,6 disulfonic acid; p-diazo diethyl aniline-2,3dihydroxy naphthalene-6 sulfonic acid; p-diazo-N ethyl N hydroxy ethylaniline-2,3 dihydroxy naphthalene-6 sulfonic acid; p-diazo diethylaniline-1 naphthol-8 amino 3,6 disulfonic acid; o-anisidine diazo-lnaphthol-S sulfonc acid; o-anisidine diazo-1 naphthol-6 amino-3 sulfonicacid, and 6 benzoyl amino-4 methoxy toluene-3 diazo salt of 1 naphthol-6amino-3 sulfonic acid.

12. The method of producing copy by spirit duplication with a masterimaged with a material containing a large proportion of acoupler-stabilized diazo complex compound lacking in color transfervalue and which is incapable of coupling reaction without adjustment ofpH, comprising contacting the imaged surface of the master with copysheets wetted with a fluid containing a solvent for thecoupler-stabilized diazo complex compound and a compound for adjustmentof the pH to a level where reaction can take place between the couplerand diazo components of'the compound to form the corresponding azodyestufl whereby some of the couplerstabilized diazo complex compoundtransfers from the imaged areas of the masterto the copy sheet uponcontact where reaction takes place to form the azo dyestuff.

13. The method of producing copy by spirit duplication with a masterimaged with a composition containing a large proportion of acoupler-stabilized diazo complex compound substantially free of anycolor transfer value and which remains non-coupling until adjustment ofpH to a higher pH level, comprising contacting the imaged master with acopy sheet wetted with a fluid containing a solvent for thecoupler-stabilized diazo complex compound and a base for adjustment ofthe pH to a level where coupling reaction can take place between thediazo and coupler components of the compound to form the azo dyestuffwhereby some of the coupler-stabilized diazo complex compound, transfersfrom the imaged areas of the master to the copy sheetwhere reactiontakes place to form the azo dyestuif.

14. The method. of producing copy comprising'the steps ,of imaging amaster with a composition substantially free of any dye color andcontaining a high proportion of a coupler-stabilized diazo complexcompound soluble in a medium selectedfrom the group consisting ofalcohol and water, wetting the surface of a copy sheet with a fluidcontaining a solvent for. the coupler and a base for adjusting the pH topermit coupling reaction between the diazo and coupler components of thecompound, contacting the wetting copy sheet with the imaged surfaceofthe master to effect transfer of some of the imaging material from thecopy sheetwhere reaction takes place to form the azo dyestufi.

1 5. The rnethod,of producing copy, comprising the steps of imaging amaster'with a composition substantially free of any dye color andcontaining a high proportion of a coupler-stabilized diazo complexcompound which is non-coupling until adjustment of the pH, wetting thesurface of a copy sheet with a fluid containing a solvent for thecoupler-stabilized diazo complex compound and a medium for adjusting thepH to permit coupling reaction between the diazo and coupler componentsof the compound to form the corresponding azo dyestuff, contacting thewetted copy sheet with the imaged surface of the master to leach some ofthe couplerstabilized diazo complex compound for transfer from theimaged master to the copy sheet where reaction takes place upon pHadjustment to form the azo dyestufi therein.

References Cited in the file of this patent UNITED STATES PATENTS ThorpeSept. 25, Dreyfus et a1. Sept. 29, Neidich Feb. 14, Neidich Oct. 8,Spoeni et a1. Oct. 10, Holik May 29, Yutzy et al. May 13, Klimkowski etal Apr. 14, Klimkowski et a1 May 29,

12. THE METHOD OF PRODUCING COPY BY SPIRIT DUPLICATION WITH A MASTERIMAGED WITH A MATERIAL CONTAINING A LARGE PROPORTION OF ACOUPLER-STABILIZED DIAZO COMPLEX COMPOUND LACKING IN COLOR TRANSFERVALUE AND WHICH IS INCAPABLE OF COUPLING REACTION WITHOUT ADJUSTMENT OFPH, COMPRISING CONTACTING THE IMAGED SURFACE OF THE MASTER WITH COPYSHEETS WETTED WITH A FLUID CONTAINING A SOLVENT FOR THECOUPLER-STABLIZED DIAZO COMPLEX COMPOUND AND A COMPOUND FOR ADJUSTMENTOF THE PH TO A LEVEL WHERE REACTION CAN TAKE PLACE BETWEEN THE COUPLERAND DIAZO COMPONENTS OF THE COMPOUND TO FORM THE CORRESPONDING AZODYESTUFF WHEREBY SOME OF THE COUPLERSTABILIZED DIAZO COMPLEX COMPOUNDTRANSFERS FROM THE IMAGED AREAS OF THE MASTER TO THE COPY SHEET UPONCONTACT WHERE REACTION TAKES PLACE TO FORM THE AZO DYESTUFF.